Optical Sensor Burnout Protection via Tunable Filter Shutter

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Solution Overview

Problem

Optical sensors are prone to burnout due to high-intensity light exposure, such as sunlight or laser jammers, requiring rapid reaction times to prevent damage, which existing technologies struggle to address effectively.

Innovation Solution

A shutter system comprising a fixed filter and a programmable filter, electrically coupled to a voltage source, which can be switched between ON and OFF states by shifting the passband wavelength of the programmable filter away from the fixed filter's passband, allowing or blocking high-intensity light from reaching the sensor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a shutter system with programmable filter is used to protect optical sensors from high-intensity light, then the sensor protection capability is improved, but the device complexity increases

Engineering Contradiction:
Improvesensor protection capabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The shutter system is divided into multiple functional components: a fixed filter with first and second passbands, a programmable filter with tunable passband, and a voltage source for control. This segmentation allows each component to perform a specific function - the fixed filter provides baseline protection while the programmable filter dynamically adjusts to block specific wavelengths, achieving effective sensor protection through coordinated action of simpler subsystems.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The programmable filter incorporates a voltage source that dynamically adjusts the passband wavelength of the filter in response to detected light intensity. This dynamic tuning capability allows the system to adapt to varying illumination conditions and respond to high-intensity light events in real-time, improving sensor protection without requiring a completely complex static system.

Inventive Principle:
Principle #15Dynamics

2Speed

If the shutter system switches rapidly to block high-intensity light, then the response time is improved, but the loss of useful light signal increases

Engineering Contradiction:
Improveresponse timeVSAvoidloss of useful light signal
Core Design Contradiction:
SpeedVSLoss of energy

Solution Approach 1:

The fixed filter is designed with specific passbands positioned to allow normal operational wavelengths while the programmable filter targets specific wavelengths for dynamic blocking. This local differentiation ensures that the shutter system blocks only harmful wavelengths during high-intensity events while preserving transmission of useful signals at other wavelengths, minimizing overall signal loss while maintaining rapid response capability.

Inventive Principle:
Principle #3Local quality

3Object-affected harmful factors

If the passband wavelength of the programmable filter is shifted away from the fixed filter's passband, then the light blocking capability is improved, but the signal transmission for narrowband light sources decreases

Engineering Contradiction:
Improvelight blocking capabilityVSAvoidsignal transmission
Core Design Contradiction:
Object-affected harmful factorsVSLoss of energy

Solution Approach 1:

The dual-passband filter design segments the spectral response into distinct regions: the fixed filter provides continuous coverage with first and second passbands, while the programmable filter adds dynamic third passband capability. This segmentation enables selective blocking of harmful wavelengths without uniformly affecting all signal wavelengths, as each filter component can be independently optimized for its specific function.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The programmable filter utilizes voltage-controlled parameter changes to dynamically adjust its passband wavelength. By changing the electrical parameter (voltage applied to the voltage source), the system can shift the optical passband to block specific harmful wavelengths while maintaining transmission of useful signals, achieving adaptive protection without permanent signal loss.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The system effectively protects optical sensors from high-intensity light by rapidly switching between light transmission and blockage, preventing damage while maintaining minimal signal loss for narrowband light sources and allowing continuous operation near damage thresholds.

Implementation Method 1

a programmable filter, electrically coupled to a voltage source, which can be switched between ON and OFF states by shifting the passband wavelength of the programmable filter away from the fixed filter's passband

Methodology Applied
Scientific EffectElectro-Optic Effect: Electro-Optic Effects

Data Source

PatentEP3577429B1Burnout protection for optical sensors
Publication Date: 2023.03.22 RAYTHEON CO
  • EP3577429B1 patent drawingFigure 1
  • EP3577429B1 patent drawingFigure 2
  • EP3577429B1 patent drawingFigure 3

AI summary

A method and apparatus for protecting an optical sensor is disclosed. A fixed filter having a fixed passband for light transmission is placed in front of the optical sensor. A programmable filter having a variable passband for light transmission is placed in front of the fixed filter. A controllable voltage source controls a voltage at the programmable filter that shifts the passband of the programmable filter from a first state in which the passband of the programmable filter is substantially the same as the passband of the fixed filter and a second state in which the passband of the programmable filter is different than the passband of the fixed filter.